In a store such as a convenience store, a monitoring system is widespread, in which a camera that captures images of the inside of the store is installed, a monitored moving image captured by the camera is displayed on a monitor, and then, situations in the store are monitored. In the monitoring system described above, if a focused area in the monitored moving image is designated and the image of the area is enlarged to be displayed, a state of a person in the focused area can be observed in detail, and thus, it is possible to accurately and efficiently execute a monitoring operation.
In a case where the focused area in the monitored moving image is enlarged and displayed as described above, a method of so-called picture in picture (P in P) may be used, in which the enlarged image is superimposed on the monitored moving image as a sub-image. However, if the sub-image is simply superimposed and displayed only on the designated area, the original image of the designated area and portions in the vicinity thereof are hidden by the sub-image, which results in hindrance to the monitoring operation. Therefore, it is desirable to arrange the sub-image at the position different from the designated area on the monitored moving image.
In the P in P method described above, as a technology of arranging a sub-image on a position different from the designated area on the monitored moving image, a technology, in which an enlarged image of an area where an abnormality has occurred is arranged at the corner of the monitored moving image as the sub-image, is known in the related art (refer to PTL 1). In addition, a technology is known, in which a best shot of a person's face image is arranged at a region where there is no motion (stationary block), that is, at a region where a person is not present as a sub-image (refer to PTL 2).